Role of mixing in copolymerizations of styrene andn-butyl acrylate

Abstract

The effect of agitation speed and impeller type on the kinetics of emulsion copolymerization of styrene and n-butyl acrylate was investigated. It was shown that the solids content was an important variable in these studies. At low solids (30%), the impeller type and speed did not have any significant effect on the final number of particles and the overall rate of polymerization. Particle size distributions were unimodal in all the cases. At high solids (50%), some differences were observed when 2 different impellers (Rushton and A310 fluidfoil) were used. The polymerization carried out with the Rushton impeller was faster. Bimodal particle size distributions were obtained for both cases; however, the bimodality was more significant when the A310 fluidfoil impeller was used. Greater numbers of particles and unimodal particle size distributions with high rates of polymerization at 30% solids contrasted the lower numbers of particles and bimodal particle size distributions with lower rates of polymerization seen at 50% solids. These differences were attributed to the partitioning behavior of the surfactant (Triton X-405; octylphenoxy polyethoxy ethanol; Union Carbide, Danbury, CT). © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2277–2289, 1998